<!-- shop Goods -->
<template>
  <div>
    <div class="goods">
      <div class="menu-wrapper" ref="menuWrapper">
        <ul>
          <!-- 标识当前分类的 class 标识:  current -->
          <li class="menu-item" v-for="(category , index) in goods" :key="index"
            :class="{current: index===currentIndex}" @click="clickMenuItem(index)">
            <span class="text bottom-border-1px">
              <img class="icon" :src="category.icon" v-if="category.icon"> {{category.name}}
            </span>
          </li>
        </ul>
      </div>
      <div class="foods-wrapper" ref="foodsWrapper">
        <ul ref="foodsUl">
          <!-- class 预保留 food-list food-list-hook -->
          <li class="food-list-hook" v-for="(category , index) in goods" :key="index" >
            <h1 class="title">{{category.name}}</h1>
            <ul>
              <li class="food-item bottom-border-1px" v-for="(food , index) in category.foods"
                :key="index" @click="showFood(food)">
                <div class="icon">
                  <img width="57" height="57" :src="food.icon">
                </div>
                <div class="content">
                  <h2 class="name">{{food.name}}</h2>
                  <p class="desc">{{food.description}}</p>
                  <div class="extra">
                    <span class="count">月售 {{food.sellCount}} 份</span>
                    <span>好评率 {{food.rating}}%</span>
                  </div>
                  <div class="price">
                    <span class="now">￥{{food.price}}</span>
                    <span class="old" v-if="food.oldPrice">￥{{food.oldPrice}}</span>
                  </div>
                  <div class="cartcontrol-wrapper">
                    <CartControl :food="food" />
                  </div>
                </div>
              </li>
            </ul>
          </li>
        </ul>
      </div>
      <ShopCart />
    </div>
    <Food :food="food" ref="food" />
  </div>
</template>

<script>
import { mapState } from 'vuex'
// 引入滑动模块
import BScroll from 'better-scroll'
// 引入食品加减组件
import CartControl from '@/components/CartControl/CartControl'
// 引入显示详细信息的组件, 大图, 详情
import Food from '@/components/Food/Food'
// 引入购物车组件
import ShopCart from '@/components/ShopCart/ShopCart'

export default {
    data() {
        return {
            scrollY: 0, // 右侧滑动的Y轴坐标 (滑动过程时实时变化)
            tops: [], // 所有右侧分类li的top组成的数组  (列表第一次显示后就不再变化)
            food: {}, // 需要显示的food
            foodsScroll: [],
        }
    },

    components: {
      CartControl ,
      Food,
      ShopCart
    },

    computed: {
        ...mapState(['goods']),
        currentIndex() {
            // 得到条件数据
            const { scrollY, tops } = this
            // 根据条件计算产生一个结果
            const index = tops.findIndex((top, index) => {
                // scrollY >= 当前top && scrollY < 下一个 top
                return scrollY >= top && scrollY < tops[index + 1]
            })
            return index
        },
    },

    mounted() {
        // 获取当前商家的商品数据
        this.$store.dispatch('getShopGoods', () => {
            this.$nextTick(() => {
                // this.scorll = new BScroll(this.$refs.menuWrapper, {})
                this._initScroll()
                this._initTops()
            })
        })
        // this.$store.dispatch('')
    },

    methods: {
        // 初始化滚动, 列表显示之后创建
        _initScroll() {
            // 给左边的分类创建滑动效果
            new BScroll('.menu-wrapper', {
                click: true,
            })
            // 给有点的食物列表创建滑动效果
            this.foodsScroll = new BScroll('.foods-wrapper', {
                probeType: 2,
                click: true,
            })
            // 给右侧列表绑定 scroll 监听
            this.foodsScroll.on('scroll', ({ x, y }) => {
                console.log('scroll', x, y)
                this.scrollY = Math.abs(y)
            })
            // 给右侧列表绑定 scroll 结束的监听
            this.foodsScroll.on('scrollEnd', ({ x, y }) => {
                console.log('scrollEnd', x, y)
                this.scrollY = Math.abs(y)
            })
        },
        // 这个是做什么用的?
        _initTops() {
            // 1 初始化 tops
            const tops = []
            let top = 0
            tops.push(top)
            // 2 收集
            const lis = this.$refs.foodsUl.getElementsByClassName('food-list-hook')
            Array.prototype.slice.call(lis).forEach((li) => {
                top += li.clientHeight
                tops.push(top)
            })
            // 3 更新数据
            this.tops = tops
            console.log(tops)
        },

        // 点击左侧分类 使得右侧列表滑动到对应的位置
        clickMenuItem(index) {
            // 得到目标位置的 scrollY
            const scrollY = this.tops[index]
            // 立即更新 scrollY (让顶级的分类项成为当前分类)
            this.scrollY = scrollY
            // 平滑滑动右侧列表
            this.foodsScroll.scrollTo(0, -scrollY, 300)
        },
        // 显示食物详情
        showFood(food) {
          this.food = food
          // 显示子组件
          this.$refs.food.toggleShow()
        }
    },
}
</script>


<style lang="stylus" rel="stylesheet/stylus">
@import '../../../common/stylus/mixins.styl';

.goods {
  display: flex;
  position: absolute;
  top: 195px;
  bottom: 46px;
  width: 100%;
  background: #fff;
  overflow: hidden;

  .menu-wrapper {
    flex: 0 0 80px;
    width: 80px;
    background: #f3f5f7;

    .menu-item {
      display: table;
      height: 54px;
      width: 56px;
      padding: 0 12px;
      line-height: 14px;

      &.current {
        position: relative;
        z-index: 10;
        margin-top: -1px;
        background: #fff;
        color: $green;
        font-weight: 700;

        .text {
          border-none();
        }
      }

      .icon {
        display: inline-block;
        vertical-align: top;
        width: 12px;
        height: 12px;
        margin-right: 2px;
        background-size: 12px 12px;
        background-repeat: no-repeat;
      }

      .text {
        display: table-cell;
        width: 56px;
        vertical-align: middle;
        bottom-border-1px(rgba(7, 17, 27, 0.1));
        font-size: 12px;
      }
    }
  }

  .foods-wrapper {
    flex: 1;

    .title {
      padding-left: 14px;
      height: 26px;
      line-height: 26px;
      border-left: 2px solid #d9dde1;
      font-size: 12px;
      color: rgb(147, 153, 159);
      background: #f3f5f7;
    }

    .food-item {
      display: flex;
      margin: 18px;
      padding-bottom: 18px;
      bottom-border-1px(rgba(7, 17, 27, 0.1));

      &:last-child {
        border-none();
        margin-bottom: 0;
      }

      .icon {
        flex: 0 0 57px;
        margin-right: 10px;
      }

      .content {
        flex: 1;

        .name {
          margin: 2px 0 8px 0;
          height: 14px;
          line-height: 14px;
          font-size: 14px;
          color: rgb(7, 17, 27);
        }

        .desc, .extra {
          line-height: 10px;
          font-size: 10px;
          color: rgb(147, 153, 159);
        }

        .desc {
          line-height: 12px;
          margin-bottom: 8px;
        }

        .extra {
          .count {
            margin-right: 12px;
          }
        }

        .price {
          font-weight: 700;
          line-height: 24px;

          .now {
            margin-right: 8px;
            font-size: 14px;
            color: rgb(240, 20, 20);
          }

          .old {
            text-decoration: line-through;
            font-size: 10px;
            color: rgb(147, 153, 159);
          }
        }

        .cartcontrol-wrapper {
          position: absolute;
          right: 0;
          bottom: 12px;
        }
      }
    }
  }
}
</style>